1. Field of the Invention
The present invention relates to a lateral electric field type liquid crystal display device which exhibits an excellent characteristic in the viewing angle property.
2. Description of the Related Art
While the widely used TN (Twisted Nematic) system, can provide high, contrast, there is also an issue that the visual angle dependency thereof is tremendous since the liquid crystal molecule axes are raised by the perpendicular electric field. Recently, there is a strong demand to acquire same picture qualities from any directions with large-scaled monitors of TV (television sets) as well as portable information terminals. In order to fulfill such demand, it has become popular to employ systems such as the IPS (In-plane Switching) and the FFS (Fringe field Switching), with which the liquid crystal is rotated in a plane that is almost in parallel to the substrate by applying a lateral electric field that is substantially in parallel to the substrate.
Those lateral electric field systems rotate the molecule axes of the nematic liquid crystal aligned horizontally within a plane that is in parallel to the substrate by using the lateral electric field.
With the lateral electric field systems, it is possible to suppress changes in the picture quality caused depending on the viewing angle directions according to the rise of the liquid crystal molecule axes. Therefore, the viewing angle property can be improved.
However, the viewing angle property is not perfect even in the case of the lateral electric field systems, and slight shift is generated depending on the alignment directions of the liquid crystal molecules and the directions of the absorption axis of the polarization plate. With FFS in particular, the voltage-transmittance is shifted to the low voltage side when viewed from an oblique view field of the initial alignment direction of the liquid crystal.
It is therefore an exemplary object of the present invention to provide a lateral electric field type liquid crystal display device with which a fine black display can be acquired even when viewed from any viewing angles by suppressing the transmittance when viewed, from oblique viewing field at the time of black display.